Question

我有2张桌子。[用户]和[问题]

用户表具有..

UserId Name
--     ----
1      Bob
2      Ang
3      Bill

问题表有..

QuestId Description CategoryId
------- ----------  --------
0       Question0   1
1       Question1   1
2       Question2   1
3       Question3   1
4       Question4   1
5       Question5   1
6       Question6   1
7       Question7   1
8       Question9   1
9       Question9   1
10      Question10  2

现在，我要为每个[用户]选择5个随机问题。

我已经尝试过此查询。

SELECT [User].UserId,Name, QuestId, Description from Users OUTER APPLY 
(SELECT TOP 5 QuestId, Description FROM Question WHERE CategoryId=1 ORDER BY NEWID(), 
Question.Id) RandomQuestions

结果就是这样。

UserId Name QuestId Description
------ ---- ------- -----------
1      Bob  2       Question2
1      Bob  3       Question3
1      Bob  6       Question6
1      Bob  8       Question8
1      Bob  9       Question9

2      Ang  2       Question2
2      Ang  3       Question3
2      Ang  6       Question6
2      Ang  8       Question8
2      Ang  9       Question9

3      Bill 2       Question2
3      Bill 3       Question3
3      Bill 6       Question6
3      Bill 8       Question8
3      Bill 9       Question9

问题是，QuestId是随机生成的，但是如果您注意到，每个用户都有相同的生成随机问题。我希望每个用户都有不同的随机问题集。

Answer 1

使用这个：

SELECT UserId,Name,QuestId, Description
FROM   Users  a
CROSS apply (
SELECT TOP 5 Row_number() OVER(ORDER BY (SELECT NULL)) AS RowNo, *
            FROM   (SELECT TOP 5 QuestId, Description
                    FROM   Question  b
                    WHERE  a.UserId = a.UserId 
                    ORDER  BY Newid()) S
) cs

Answer 2

您需要像这样随机QuestionID

WHERE QuestId = (ABS(CHECKSUM(NEWID()) % 10)) + 1

如何在没有公共密钥的情况下联接2个表并随机生成第二个表的行

2 个答案: